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bioRxiv · 10.1101/571836

A novel Ca2+-binding protein influences photosynthetic electron transport in Anabaena sp. PCC 7120

Walter, J.·Selim, K. A.·Leganes, F.·Fernandez-Pinas, F.·Vothknecht, U. C.·Forchhammer, K.·Aro, E.-M.·Gollan, P. J.
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Abstract

Ca2+ is a potent signalling molecule that regulates many cellular processes. In cyanobacteria, Ca2+ has been linked to cell growth, stress response and photosynthesis, and to the development of specialist heterocyst cells in certain nitrogen-fixing species. Despite this, the pathways of calcium signal transduction in cyanobacteria are poorly understood, and only a few protein components are known. The current study describes a previously unreported calcium-binding protein which was called the Calcium Sensor EF-hand (CSE), which is conserved in filamentous, nitrogen-fixing cyanobacteria. CSE is shown to bind calcium, which induces a conformational change in the protein structure. Poor growth of a strain of Anabaena sp. PCC 7120 overexpressing CSE was attributed to diminished photosynthetic performance. Transcriptomics, biophysics and proteomics analyses revealed modifications in the light-harvesting phycobilisome and photosynthetic reaction center-protein complexes, and downregulated respiration.

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Walter, J., Selim, K. A., Leganes, F., Fernandez-Pinas, F., Vothknecht, U. C., Forchhammer, K., Aro, E.-M., Gollan, P. J.. 2019-03-08. A novel Ca2+-binding protein influences photosynthetic electron transport in Anabaena sp. PCC 7120. https://doi.org/10.1101/571836

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